Dr. Sasha Costanza-Chock — Berkman Fellow and Assistant Professor of Civic Media at MIT — introduces the theory of transmedia mobilization and invites us to rethink the relationship between social movements and the media opportunity structure. Based on five years of research within the immigrant rights movement in Los Angeles, the theory of transmedia mobilization involves engaging the social base of the movement in participatory media making practices across multiple platforms. This marks a transition in the role of social movement communicators from one of primarily content creation to aggregation, curation, remix, and recirculation of rich media texts through networked movement formations.